Just to add another idea of how to do it...

@a=qw(1 2 3 4 5 6 7 8 9 2 3 1 4 5 6 7 8 9 1 4);

$first=3;
$last=1;

@l{@a}=0..$#a;
@f{reverse @a}=reverse 0..$#a;
print join ' ',@a[$f{$first}..$l{$last}],"\n";
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This solves the problem by storing the first and last index of each number in %f and %l. Then you can get the whole slice between both numbers.

Maybe you want to use

@a[$f{$first}..$l{$last}>=$f{$first}?$l{$last}:$#a]
[download]

to get the complet rest of the array if the last number isn't behind the first.